Fluid pressure devices operated by hydraulic pressure or pneumatic pressure are known, particularly for expanding tubes such as those used in air conditioning coils and the like. Several hydraulic devices have been developed which are suitable for tightly gripping one end of an elongated tube while simultaneously delivering a tube expanding fluid. Among these are U.S. Pat. Nos. 3,505,846; 3,813,751, 3,962,769; and 4,189,162. None of these patents describe devices which are suitable for expanding the ends of tubes.
One of the problems which is encountered in the assembly of tube devices is the need to quickly and efficiently join tubes together, either when the unit is assembled in the field or when repairs are made. Even in factory assembly, coil units require tubes to be joined and this procedure needs to be accomplished as effectively and efficiently as possible.
The only prior art devices which are used currently to expand the ends of tubes are devices which include a split finger means which is inserted in the tube. As the split fingers expand or flair out the end of the tube, material is squeezed between the fingers, leaving longitudinally extending ridges or raised portions. These raised portions of material cause several problems, both in obtaining a good junction and strong seal, and in requiring the use of much more silver solder or other sealing material.
Accordingly, it would be of great advantage in the art if a means could be provided for expanding the ends of tubes without causing the tube to be pinched or otherwise deformed during the expansion process. It is an object of this invention to provide a device for obtaining this advantage.
Another advantage in the art would be obtained if the ends of tubes could be expanded using a simple, effective device which can accommodate tubes of different thicknesses. At the present, split finger devices are not effectively adjustable to accommodate different tube wall thicknesses. This is also an object of this invention, to provide a device which can easily be adjusted for tubes of different wall thicknesses.
Other objects will appear hereinafter.